Introduction - Wind Energy: Renewable Energy and the Environment - page 7

FIGURE 1.8 Smith - Putnam wind turbine, 1250 kW. (Photo from archive files of Carl Wilcox. With permission.)
Testing of the wind turbine started in October 1941, and in May 1942, after 360 h of operation,
cracks were discovered in the blades near the root. The root sections were strengthened and the cracks
were repaired by arc welding. A main bearing failed in February 1943, and it was not replaced until
March 1945 because of a shortage of materials due to World War II. After the bearing was replaced, the
unit was operated as a generating station for 3 weeks when a blade failed due to stress at the root. Total
running time was only around 1,100 h. Even though the prototype project showed that a wind turbine
could be connected to the utility grid, it was not further pursued because of economics. The industrial
photos of the construction of the Smith-Putnam wind turbine are available online [16].
Percy Thomas, an engineer with the Federal Power Commission, pursued the feasibility of wind
machines. He compiled the first map for wind power in the United States and published reports on
design and feasibility of wind turbines [7].
After World War II, research and development efforts on wind turbines were centered in Europe.
E. W. Golding summarized the efforts in Great Britain [8], and further efforts are reported in the
conference proceedings of the United Nations [9]. The British built two large wind turbines. One
wind turbine was built by the John Brown Company on Costa Hill, Orkney, in 1955. The John
Brown unit was rated at 100 kW at 16 m/s, with a rotor diameter of 15 m on a 24 m tower. The wind
turbine was connected to a diesel-powered grid and only ran intermittently in 1955 due to opera-
tional problems.
The other unit was built by Enfield, based on a design by the Frenchman Andreau, and was
erected at St. Albans in 1952. The Enfield-Andreau wind turbine rotor was 24 m in diameter on a
30 m tower, with a rated power of 100 kW at 13 m/s. This unit was quite different in that the blades
were hollow, and when they rotated, the air flowed through an air turbine, connected to an alterna-
tor at ground level, and out of the tip of the blades ( Figure 1.9 ) . This unit was moved to Grand Vent,
Algeria, for further testing in 1957. Frictional losses were too large for this unit to be successful.
The French built several prototype wind turbines from 1958 to 1966. A 800 kW wind turbine was
located at Nogent Le Roi, which had a rotor diameter of 31 m and was operated at constant rotor
speed connected to a synchronous generator. The top weighed 162 metric tons and was mounted on